Some milking characteristics of Jersey cows of differing breeding index

Abstract

Abstract ‘Cups-on time’ (COT) for individual Jersey cows was measured using two techniques during six consecutive milkings in 2 consecutive weeks during peak lactation (October–November). Four groups of 15 animals included two groups with a high breeding index (HBI) of 127 and two groups with a low breeding index (LBI) of 101. HBI cows averaged 15.5 kg milk/day compared to 12.5 kg/day for the LBI cows. Morning (AM) milk weights for all groups were twice the afternoon (PM) milk weights at milking intervals of 16:8 h. The average COT at AM milkings was 7.6 min/cow compared to 5.7 min/cow at PM milkings. The average flow rate (AFR) at AM milkings was 1.33 kg/min for HBI cows and 1.13 kg/min for LBI cows. Comparable AFRs at PM milkings were 0.88 (HBI) and 0.75 kg/min (LBI). Differences related to BI in COT and AFR were not statistically significant, partly because of the large variation among individual cows within a BI group. This study showed that the increased production of Jersey cows resulting from the use of progeny tested HBI sires has not increased COT.